fluid to show penetration

[txargyll]

hi, what fluid do i nee to buy that you rub on steel that shows how your weld penetrated.
hope that makes sense but just in case not ill try and explain that again.

i have welded my bead, now i cut through the steel to see a section of my metal and bead, i have seen somewhere that a fluid can be rubbed on the section to see how far your weld has penetrated


thanks for help

 

[Paul G]

After cold cutting through the weld you then polish the cut surface.
10% nitric acid (in water) will then bring up the macro structure.

Paul G

 

[normspanners]

fluid to show penetration
Sorry I was thinking something completely different when I read that .
Suppose it highlights my deep thinking ( well I like to think that!)

anyway what Paul said

 

[txargyll]

EEK, expensive stuff, is there a known household product that will do the job?

 

[pedrobedro]

EEK, expensive stuff, is there a known household product that will do the job?

Have a look on the American welding site, Jodie did a demo of available substances that showed up weld structure, Naval Jelly was one of them you can get it on ebay or amazon.

 

[txargyll]

thanks, seen that earlier. someone else said JENOLITE , anybody tried this

 

[Maker]

I've done it with citric acid before which worked well. In order for this to work, regardless of your chemical, you need to clean and polish the surface, I used a flapwheel in my grinder, followed by increasing grits on an orbital sander and finally 1000 grit wet 'n dry paper. It worked very well.

 

[Jan]

If bought in bulk from a homebrew store, citric acid is quite inexpensive. As a homebrewer I usually have at least 500 grams of the stuff on hand which I use for a variety of tasks. It's good for descaling kettles and coffee machines, plus a spoonful or two in a 'dry' toilet topped up with freshly boiled water will remove most stains in a couple of hours. At a pinch you can add 200-300 grams into your car's coolant system to clear out a lot of the blockages if left in for a few days of normal use. Preferably not at this time of year as it should only have a 50% solution of anti freeze in it.

 

[Maker]

It also removes rust but someone (MattF I think) said it can damage precision surfaces or something and is not recommended if other methods (Like electrolysis) can be used .

 

[Robotstar5]

I'm sure someone suggested battery acid in another thread?.

 

[backpurge]

Potassium persulphate crystals dissolved in water work well on carbon steel and are a lot safer to store and handle than acid

 

[Mid Wales welder]

The surface needs to be polished really well and then all of the above suggestions plus pickling paste (used to get oxidation colour from stainless welds) works well too.

 

[outofthefire]

One of the apprentices was showing me some pics of their welds from college the other day and besides the nitric acid test on the cross section, they were using a red dye down the length of the weld that showed where it hadn't penetrated properly.

 

[AdrianH]

On the latest youtube by weldingtipsandtricks he was using a rust remover by Loctite as an etchant to show penetration of stick welds. So that looks a good and cheap way of doing it.

Adrian

 

[outofthefire]

http://www.mig-welding.co.uk/wiki/Dye_Penetrant

That sounds like the stuff, it did look good it showed up a lot of imperfections in the whole weld (Can't see any pics in the link is that me or the webpage)

 

[backpurge]

That sounds like the stuff, it did look good it showed up a lot of imperfections in the whole weld (Can't see any pics in the link is that me or the webpage)

It shows surface imperfections but not penetration profile

 

[Rocketman]

In my first job as apprentice the company I worked for did high spec structural steel. On quite a lot of the jobs it was required that a certain amount of the work was xray / ultrasonic tested. I was in the drawing office but spent a certain amount of time in the factory as part of the apprenticeship.

I remember I had done some welding on some of the butt weld joints on huge curved roof structure. As I hadn't any proper welding certs I wasn't supposed to be doing it. Anyway funnily enough the ones I was working on were inspected and passed. I often go to the shopping centre they are in and always look at them .